Ex Parte Cao

Board of Patent Appeals and Interferences

Oct 19, 2010

10420643 (B.P.A.I. Oct. 19, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte BO CAO
__________

Appeal 2010-003050
Application 10/420,643
Technology Center 1600
__________

Before CAROL A. SPIEGEL, TONI R. SCHEINER, and
FRANCISCO C. PRATS, Administrative Patent Judges.

PRATS, Administrative Patent Judge.

DECISION ON APPEAL1
This appeal under 35 U.S.C. § 134 involves claims to a method of
counting cells in blood samples. The Examiner rejected the claims as
obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We reverse.

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.
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STATEMENT OF THE CASE
“HIV infection and the progress of AIDS disease are marked by a
decrease in CD4+ T-lymphocytes. Absolute CD4+ T-lymphocyte counts and
the change in these counts over time are clinically important markers of viral
infection” (Spec. 1).
The Specification states that the “present invention answers the urgent
need for an inexpensive, technically simple, accurate method for detecting
and optionally quantifying a specific target cell, such as a CD4+ T-
lymphocyte, in a sample, such as a sample of whole blood” (id. at 3).
Claims 1, 3-22, 25-27, 29-30, 34-41, 46, and 71-79 stand rejected and
appealed (App. Br. 2).2 Claim 1, the only independent claim, is
representative and reads as follows:
1. A method for observing a target cell in a sample of
untreated or substantially untreated whole blood, comprising:
a) providing a sample of untreated or substantially
untreated whole blood that is suspected of containing a target
cell;
b) providing a solid substrate, said solid substrate
comprising:
a multi-layered composition comprising:
(i) a first component on the surface of said solid
substrate, said first component comprises polyanion
layers and polycation layers in an alternating
arrangement substantially parallel to the surface of said
solid substrate;
(ii) a second component contacting said first
component, said second component comprises a high
affinity binding pair comprising a first member and a
second member, wherein the first member binds to said

2 “Second Amended Appeal Brief” entered August 27, 2009.
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first component, the second member binds to said first
member; and
(iii) a third component comprising a specific
binding agent that binds to said second member of said
second component;
c) contacting said sample with said solid substrate;
d) incubating said sample on said solid substrate for a
period of time sufficient to permit said binding agent to
specifically bind said target cells present in said sample to said
solid substrate;
e) washing said solid substrate; and
f) manually observing and counting the number of
said target cells bound to said solid substrate by light
microscopy.

The following rejections are before us for review:
(1) Claims 1, 3-22, 25-27, 29-30, 34-41,46, and 71-79, rejected under
35 U.S.C. § 103(a) as obvious over Wohlstadter,3 Diederich,4 and
Westbrook5 (Ans. 3-15);
(2) Claim 46, rejected under 35 U.S.C. § 103(a) as obvious over
Wohlstadter, Diederich, Westbrook, and Connolly6 (Ans. 16-17); and
(3) Claims 74, 75, and 78, rejected under 35 U.S.C. § 103(a) as
obvious over Wohlstadter, Diederich, Westbrook, and McGall7 (Ans. 17-20).

3 U.S. Patent No. 6,207,369 B1 (issued March 27, 2001).
4 EP 0 762 122 A1 (published March 12, 1997) (as machine translated).
5 U.S. Patent No. 6,025,126 (issued February 15, 2000).
6 U.S. Patent No. 4,933,278 (issued June 12, 1990).
7 U.S. Patent Application Publication No. 2001/0049108 A1 (published
December 6, 2001).

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OBVIOUSNESS
The Examiner cites Wohlstadter as teaching a method of identifying
and counting target cells in blood samples by applying the sample to a multi-
layered substrate that has a binding agent specific for the target cells on its
surface (Ans. 4).
The Examiner concedes that, while Wohlstadter’s substrate can
include a polyanion or polycation layer, Wohlstadter does not teach that the
substrate has alternating polyanion and polycation layers as required by
claim 1 (id. at 5). The Examiner cites Diederich to address this deficiency
(id.).
Based on the two references’ teachings, the Examiner reasons that an
ordinary artisan would have been prompted to modify Wohlstadter’s
cell-binding substrate to include Diederich’s alternating
polyanion/polycation layers because doing so would provide “the added
advantage of allowing a precisely controlled amount of molecules to be
immobilized on the multilayered composition as explicitly taught by
Diederich et al (page 2, paragraph 6 of the English translation)” (id. at 6).
In addition, the Examiner reasons that applying Diederich’s
alternating polyanion/polycation layers to Wohlstadter’s cell detection
methods would have been expected to yield “predictable results because the
known technique of using the alternating polyanion and polycation layers as
taught by Diederich et al predictably results in layers useful in the
performance of affinity-based assays” (id. at 6-7).
The Examiner also concedes that “neither Wohlstadter et al nor
Diederich et al teach manually observing and counting [bound cells] with a
light microscope” as also required by claim 1 (id. at 7).
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To meet that deficiency, the Examiner cites Westbrook as disclosing
the “detection of visually detectable labels with bound (i.e., fixed) cells
using light microscopy, and wherein an observer manually counts the cells
(column 18, lines 5-20). Westbrook also teaches use of the light microscope
has added advantage of being simple and rapid” (id.).
Based on these teachings, the Examiner concludes that an ordinary
artisan would have considered it obvious to modify the detection methods of
Wohlstadter, viewed in light of Diederich, “so that the observation and
counting is performed manually by light microscopy as taught by Westbrook
to arrive at the instantly claimed method with a reasonable expectation of
success” (id.). The Examiner reasons that an ordinary artisan would have
been prompted to do that “because said modification would have resulted in
a method having the added advantage of detection that is simple and rapid as
explicitly taught by Westbrook” (id.).
Appellant contends, among other things, that the Examiner’s prima
facie case of obviousness, “is merely a combination of independently known
prior art by hindsight. It is well established that a patent composed of
several elements is not proved obvious merely by showing that each of its
elements was independently known in the prior art” (App. Br. 8 (citing
United States v. Adams, 383 U.S. 39 (1966))).
In particular, Appellant urges, the mere mention in Wohlstadter that
its binding domains may be used in assays using detection techniques other
than electrochemiluminescence “does not give a person with ordinary skill
in the art any reason to select the method of using the binding domains of
Wohlstadter in combination with the alternating polyionic layers of Dietrich
[sic] and the light microscopy of Westbrook” (id. at 14).
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We agree with Appellant that the evidence of record does not support
the Examiner’s position that an ordinary artisan viewing the cited references
would have been prompted to practice the methods recited in claim 1.
As our reviewing court recently stated, “it is not enough to simply
show that the references disclose the claim limitations; in addition, ‘it can be
important to identify a reason that would have prompted a person of
ordinary skill in the art to combine the elements as the new invention does.’”
Transocean Offshore Deepwater Drilling, Inc. v. Maersk Contractors USA,
Inc., --- F.3d ----, 2010 WL 3257312 at *4 (Fed. Cir. 2010) (quoting KSR
Int’l Co. v. Teleflex Inc., 550 U.S. 398, 401 (2007)).
Ultimately, therefore, “[i]n determining whether obviousness is
established by combining the teachings of the prior art, the test is what the
combined teachings of the references would have suggested to those of
ordinary skill in the art.” In re GPAC Inc., 57 F.3d 1573, 1581 (Fed. Cir.
1995) (internal quotations omitted).
In the instant case, claim 1 recites a method for observing a target cell
in a sample of untreated or substantially untreated whole blood. The sample
is incubated with a substrate, thereby allowing the target cells in the sample
to bind to a specific binding agent attached to the substrate. After washing,
the bound cells are manually observed and counted by light microscopy.
Claim 1 also requires the substrate to have a specific multi-layered
composition. In addition to the cell-specific binding agent, claim 1 requires
the substrate to include, attached to the surface of a solid substrate, a
component made up of polyanion layers and polycation layers in an
alternating arrangement substantially parallel to the surface of the solid
substrate.
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We acknowledge, as the Examiner argues, that Wohlstadter teaches a
process of counting the number of cells of a particular target cell type in a
biological sample, such as blood, by contacting the sample with a substrate
having an attached cell-specific binding agent, and using
electrochemiluminescent (ECL) techniques to detect and quantify the bound
cells (see Wohlstadter, col. 51, l. 8, through col. 52, l. 29). While
Wohlstadter does not appear to mention using a light microscope to count
the cells, Wohlstadter does disclose that “[o]ther assay techniques that may
be combined with ECL assays and/or used alone with the [specific binding
substrate] of the invention include chemiluminescent based label, fluorescent
based assays, enzyme-linked assay systems, electrochemical assays . . .
and/or resonance detection (e.g., surface plasmon and acoustic techniques)
assay systems” (id. at col. 52, ll. 44-50).
We also acknowledge Westbrook’s disclosure of an assay method that
uses a light microscope to manually determine whether visually detectable
probes become bound to target sequences on the chromosomes of fixed cells
(Westbrook, col. 18, ll. 4-18). As Westbrook discloses, the “use of a
visually detectable label allows a means of assessing the presence of the
[target] chromosome through the application of light microscopy, providing
a significant advantage in terms of expertise required to carry out the assay.
The methods are simpler and more rapid than previously available” (id. at
col. 7, ll. 24-29).
However, even assuming for argument’s sake that an ordinary artisan
would have been prompted to use a light microscope to count target cells
from a blood sample applied to Wohlstadter’s substrate, we are not
persuaded that the artisan would also have been prompted to modify
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Wohlstadter’s substrate to include Diederich’s alternating
polyanion/polycation layers. In particular, when the overall teachings of
Diederich are viewed as a whole, we are not persuaded that they support the
Examiner’s proposed combination of Diederich with Wohlstadter and
Westbrook.
The precise teachings in Diederich are less clear than they might be,
perhaps due to the nature of the machine translation (see Diederich,
generally). At any rate, Diederich discloses a “[s]olid phase optical
biosensor . . . which has receptor biomolecules for the specific recognition of
analytes utilising the Forster energy transfer (Resonant Energy Transfer;
RET) between two fluorescent dyes F1 and F2” (Diederich, abstract).
Diederich discloses that its biosensor “comprises a transparent carrier
supporting alternating polyanion and polycation layers” with a layer of
biotin molecules attached to the uppermost polycation layer, a layer of
avidin molecules attached to that biotin layer, and a layer of analyte-specific
biotinylated antibodies attached in turn to the top-most layer of avidin
molecules (id.; see also p. 3, ¶ 6; also Fig. 1).
Diederich discloses that, like previous similar sensors, its sensors can
detect analytes such as hormones, enzymes, proteins, carbohydrates, nucleic
acids, pharmacologically active substances, such as toxins, and others in
liquid samples of biological origin (id. at p. 1, ¶ 2 (“Analyten, like
hormones, enzymes, other proteins, coal hydrates, nucleic acids,
pharmakologische active substances, to prove Toxine and other in liquid
samples of biological origin”)).
However, according to Diederich, previous analyte-binding substrates
that use fluorescent resonant energy detection methods apparently produce
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less than accurate results (see id. at p. 1, ¶ 5 (“For the quantification of the
Analyten concentration by means of forest he energy transfer it affects itself
with the fact unfavorably that the distance between energy Donor and -
acceptor depending upon local surface finish irregularly varies, which
generally brings an increase to the system-dependent measurement
inaccuracy with itself” (emphasis added)); see also, id. at p. 1, ¶ 7 (“A
further disadvantage with the conception of bio sensors is the often
nonspecific reciprocal effect of proteins with the fixed phase surface. This
leads to the adsorption by means of hydrophober or ionischer interactions, is
unwanted, does not lead to not reproducible results and to the decrease of
the measuring accuracy” (emphasis added))).
In contrast, Diederich discloses that substrates employing the
alternating polyanion/polycation layers yield accurate and reproducible
results in fluorescent resonant energy transfer assays (see id. at p. 2, ¶ 4
(“The detection of the connection of the Analyten effected via forest he
energy transfer and is reproducible and in their concentration dependence
regular by a molecularly well-defined mutual arrangement of energy Donor
and - acceptor. The surface is passivated at the same time against
nonspecific adsorption by proteins”)).
Thus, in our view, an ordinary artisan viewing the teachings of
Diederich (such as they are) as a whole would have reasoned that the
purpose of arranging the layers in the manner described in the reference,
including the alternating polyanion/polycation layers, was to optimize the
substrate for fluorescent resonant energy detection methods.
However, rather than the manual detection methods required in
Appellant’s claim 1, Diederich’s fluorescence detection methods use
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machines, such as spectrophotometers, to measure the fluorescent signal
from the bound analytes (see id. at p. 3, ¶ 2 (“The forest he energy transfer
can be measured in usual fluorescence spectrometers, in addition, in
particularly laid out devices for a Energietransfer Immunosensor. By means
of suitable calibration curves then the concentration of the Analyten in the
analysis liquid can be determined”)).
We acknowledge, as the Examiner points out, Diederich’s disclosure
that its “invention is above all characterized by the use of Polykationen and
Polyanionen for the setting up the multi-layer” (id. at p. 2, ¶ 5). We also
note Diederich’s apparent disclosure that its multi-layered arrangement
allows control of the stoichiometry of biotinylated binding agents applied to
the substrate (id. at p. 2, ¶ 6 (“The portion of the biotinylierten cation
equivalents can be adapted to the desired requirements over the
Stöchometrie”)).
However, as noted above, when the overall disclosure of Diederich is
considered, Diederich teaches that the alternating layers’ purpose was to
optimize detection methods that use fluorescent energy transfer, a detecting
method that does not involve the manual measurement required by claim 1.
Moreover, we do not see, and the Examiner does not point to, any clear
teaching in Diederich, or in the knowledge generally available in the art, that
would have suggested that, when using a light microscope to manually count
cells bound to Wohlstadter’s substrate, it would be desirable, or even
suitable, to modify that substrate to include the alternating
polyanion/polycation arrangement required by claim 1.
Thus, we are not persuaded that an ordinary artisan, prompted to use a
light microscope to count target cells from a blood sample applied to
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Wohlstadter’s substrate, would also have been prompted to modify
Wohlstadter’s substrate to include Diederich’s alternating
polyanion/polycation layers. That is, we are not persuaded that an ordinary
artisan would have been prompted to make both of the Examiner’s proposed
modifications to Wohlstadter’s process.
Accordingly, we agree with Appellant that the Examiner has not made
a prima facie case of obviousness with respect to claim 1. We therefore
reverse the Examiner’s obviousness rejection of claim 1, as well as its
dependent claims 3-22, 25-27, 29-30, 34-41,46, and 71-79, over
Wohlstadter, Diederich, and Westbrook.
The Examiner also rejected claim 46 as obvious over Wohlstadter,
Diederich, Westbrook, and Connolly (Ans. 16-17). Claim 46 recites “[t]he
method of claim 1 wherein said counting of said target cells bound to said
solid substrate may be used to calculate the absolute number of said target
cells in a given volume of said sample.”
The Examiner cited Connolly to meet the features recited in claim 46
(id. at 16). However, as the Examiner pointed to no disclosure in Connolly
that remedies the deficiencies of Wohlstadter, Diederich, and Westbrook,
discussed above with respect to claim 1, we also reverse the Examiner’s
obviousness rejection of claim 46.
The Examiner also rejected claims 74, 75, and 78 as obvious over
Wohlstadter, Diederich, Westbrook, and McGall (id. at 17-20).
Claims 74, 75, and 78 depend from claim 1 and limit the polyanion
and of claim 1 to a specific polymer (see App. Br. 28 (Claims Appendix)).
The Examiner cited McGall to meet the specific polymer feature recited in
claims 74, 75, and 78 (Ans. 18).
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However, as the Examiner points to no disclosure in McGall that
remedies the deficiencies of Wohlstadter, Diederich, and Westbrook,
discussed above with respect to claim 1, we also reverse the Examiner’s
obviousness rejection of claim 74, 75, and 78.
SUMMARY
We reverse the Examiner’s rejection of claims 1, 3-22, 25-27, 29-30,
34-41,46, and 71-79 under 35 U.S.C. § 103(a) as obvious over Wohlstadter,
Diederich, and Westbrook.
We also reverse the Examiner’s obviousness rejection of claim 46
over Wohlstadter, Diederich, Westbrook, and Connolly.
We also reverse the Examiner’s obviousness rejection of claims 74,
75, and 78 over Wohlstadter, Diederich, Westbrook, and McGall.

REVERSED

dm

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